This invention relates to a combustor for a gas-or liquid-fuelled turbine.
A turbine engine typically comprises an air compressor, at least one combustor and a turbine. The compressor supplies air under pressure to the combustor or combustors, such air being utilized for both combustion and cooling purposes. Various ways of allocating the air for the two purposes have been proposed. In the normal arrangement a proportion of the air is mixed with the fuel while the remaining air supplied by the compressor is utilized to cool the hot surfaces of the combustor and/or the combustion gases, (i.e. the gases produced by the combustion process).
Environmental considerations and legislation relating thereto continue to drive down the acceptable levels of harmful combustion emissions (specifically NO.sub.x and CO) during operation of such engines. At the same time engineers strive to improve the efficiency of the engines, usually through higher operating temperatures which unhelpfully tend to increase the harmful emissions specifically of NO.sub.x ; they also look for simpler designs in order to reduce the costs of manufacture and maintenance. Inevitably, there is a conflict in establishing these objectives and compromises have to be made.
The present invention seeks to provide a combustor of relatively simple construction wherein efficient operation (including efficient cooling) is achieved with the production of harmful emissions kept as low as possible.